The present invention relates to an absorption type refrigerating machine and, more particularly, to large scale multi-stage absorption type refrigerating machine used in area heating and cooling systems for attaining a high efficiency.
A conventional heat pump absorption heating and cooling apparatus is proposed in, for example, Japanese Patent Laid-Open No. 49,465/1984, in which chilled water flowing into an evaporator works as a low temperature heat source, and cooling water flowing into an absorber and condenser works as hot water, and heat is removed to the exterior of the apparatus.
In the above conventional heat pump type absorption heating and cooling apparatus, it has been proposed to respectively divide the evaporator, the absorber, a regenerator, and the condenser into at least two parts through a partitioning wall, with each divided component being combined and constructed for at least two independent absorption solution cycles, in which the chilled water flows into a first evaporator and a second evaporator from a side having a high temperature level, the cooling water flows into a first absorber and a second absorber from a side having a low temperature level, and, after that, the cooling water, having been heated to the highest temperature, flows out from the first condenser through a second condenser.
In general, with a large scale absorption type refrigerating machine, an amount of the chilled water and an amount of the cooling water inevitably increases, and, accordingly, any necessary associated equipment such as a conveying pump, piping, a cooling tower, etc. naturally becomes relatively large sized.
Additionally, in many cases the large-scale absorption type refrigerating machine is used in an area heating and cooling system, and is subject to restrictions imposed due to an installation space, building size, the land for accommodating the refrigerating machine, etc.
With respect to the chilled water, for example, though the chilled water temperature in the conventional general absorption type refrigerating machine is 12.degree. C. at the inlet and -7.degree. C. at the outlet, consideration must be given to the fact that the quantity of chilled water is lowered by 70% thereby resulting in a difference in temperature at the inlet or outlet of 1.4 times such as, for example, 13.degree. C. at the inlet and -6.degree. C. at the outlet.
Moreover, with respect to the cooling water, for example, though the cooling water temperature in the conventional general absorption type refrigerating machine is 32.degree. C. at the inlet and -37.4.degree. C. at the outlet, consideration must be given to the fact that the volume of cooling water is lowered 90% by providing a difference in temperature of 1.1 times such as 32.degree. C. at the inlet and -38.degree. C. at the outlet.
The reduction in the quantity of water lowers an electric power consumption and economizes energy, however, a problem arises in that the efficiency of the refrigerating cycle is lowered by virtue of the above noted increase in the temperature differences.
Even in the technique described in the above-identified Japanese Patent Laid-Open No. 49,465/1984, the efficiency of the refrigerating cycle is unsatisfactory with a large scale refrigerating machine particularly for use in area heating and cooling systems.